Ten Highlights from the History of Audiology

The measurement and management of hearing disorders has a long history. As early as the 4th century BC, Hippocrates wrote extensively on the causes of hearing disorders. Later, the Enlightenment brought a flurry of activity focused on tests to differentiate among the various causes and types of hearing loss. Throughout most of recorded history, however, the measurement and management of hearing loss remained the province of medical professionals. The modern era of audiology is only 75 years old. It began with a book on clinical audiometry by Cordia C. Bunch in 1943. Several signal milestones mark the progress of audiology over the past three quarters of a century.

Event #1 1943: The Publication of Clinical Audiometry by C.C. Bunch

Cordia Bunch was a graduate student in psychology at the University of Iowa in 1919 when Carl Seashore, creator of the now famous Seashore Musical Aptitude Tests, convinced Bunch to construct a device to measure auditory thresholds across a broad frequency range. Bunch not only built the device but went on to test the patients of a local otolaryngologist, L.W. Dean. For the next 20 years Bunch gathered air-conduction audiograms on patients and wrote articles about them. Bunch laid the foundation of audiology by vividly demonstrating the many contributions that an audiological specialist could offer to hearing-impaired persons.

His publications spanned an amazingly diverse subject matter. Here is only a partial list of the topics covered:

• Use of the audiometer;
• Effect of age on audiometric thresholds;
• Importance of measuring thresholds at frequencies above the conventional audiometric range;
• Occupational and traumatic deafness;
• Progression of loss in otosclerosis;
• Deafness in aviators;
• Conservation of hearing in industry;
• Race and gender variations in hearing thresholds;
• Hearing aids;
• Otitis media;
• Calculating percentage of loss for medico-legal purposes;
• Effect of removal of one cerebral hemisphere, and
• Effect of absence of organ-of-Corti on the audiogram.

Event #2: 1946: Speech Audiometry for Hearing Aid Selection

In 1943, in the midst of WWII, the Army assigned Captain Raymond Carhart to head the acoustic division at Deshon General Hospital in Butler, Penn. He was ordered to provide aural rehabilitation and to dispense hearing aids to army personnel coming home with hearing loss. As a trained speech scientist, Carhart looked beyond the technical engineering aspects of hearing aids, sidestepped the issue of selective amplification, and focused instead on how aids actually helped users in everyday speech communication. Using the spondee words and 50-item single-syllable PB words developed at the Harvard Psycho-Acoustic Laboratory, Carhart devised a method for evaluating how well the hearing aid user could understand speech: the spondee words to determine the speech reception threshold (SRT), and the PB lists to evaluate how well the user could understand single words presented well above the (SRT). Carhart made many other contributions to our profession but the invention of speech audiometry remains his towering achievement.

Event #3 1951: Identifying Auditory-Specific Perceptual Disorder

The observations that producing and receiving language could be degraded by brain injury, the aphasias, had been analyzed and debated extensively by the end of the 19th Century.

Chronology of Key Audiology Milestones